1. Field of the Invention
This invention relates to an emergency locking device used in a seatbelt system for reliably locking an occupant restraining webbing in an emergency of a vehicle.
2. Description of the Prior Art
Heretofore, there has been proposed a seatbelt system for automatically fastening a restraining webbing to an occupant after he has been seated. In said seatbelt system, a slider is slidably guided in a guide rail laid on a vehicle body, an outer end of the webbing is secured to said slider, and the slider is driven along the guide rail, whereby the outer end of the webbing is caused to approach or recede from an occupant's seat, thereby fastening the webbing to or unfastening same from the seated occupant.
In said automatically fastening type seatbelt system, it is necessary that said slider should be positively engaged with the vehicle body at an automatically fastening position to which said slider reaches after moving in a direction of the occupant's seat along the guide rail. More particularly, in an emergency of the vehicle such as a collision, overturn or the like of the vehicle, a high tension is generated in the webbing due to a colliding inertial force of the occupant. Hence, it is necessary to make the vehicle body reliably support the tension, so that the occupant can be reliably restrained by the webbing.
From this reason, heretofore, there has been proposed means of preventing the slider from moving by use of a locking device such as a solenoid driven by an electric power source of the vehicle when the slider reaches the automatically fastening position. However, such means has been complex in construction and tended to cause an unexpected accident due to interruption of power supply in a collision of the vehicle.